Is it true, as some scientists believe, that to understand words like "spike" (in the volleyball sense) the brain has to "mentally" retrace the sequence of motor commands that accomplish the action? According to a study just published as a cover story in the December issue of Brain Research and conducted with the participation of scientists from SISSA, the International School for Advanced Studies of Trieste, the high-level motor expertise of subjects (in the case at hand of the volleyball players who responded to instructions to perform volleyball-specific actions) modulates the involvement of the brain motor areas in understanding the actions. The effect of experience is a novelty that challenges some recent hypotheses, making the theoretical picture more complex.